Trilobites are the most commonly found fossil arthropods, the family of animals that includes spiders, insects and crustaceans, all having jointed legs and an outer hard skeleton. They bear a strong resemblance to modern woodlice. All trilobites were marine, some could swim and float, others forms were blind, possibly living in deep water, but most forms were shallow water dwellers. They are most commonly found preserved in limestone and shale. They range in size from only a few millmetres to several tens of centimetres in length. They first appeared during the Cambrian Period, about 550 million years ago and become extinct in the Permian Period 280 million years ago.
**Each piece is unique so will vary in size and pattern.